Gastric cancer originates in the mucosal epithelial cells of the innermost layer of gastric wall, and it can occur in various parts of the stomach, such as gastric antrum, lesser curvature and the anterior and posterior walls thereof, fundus and cardia of the stomach, gastric body, gastroesophageal junction and the like. There are many forms of gastric cancer observed by the naked eye or gastroscope, such as superficial type, mass type, ulcerative type, invasive type, and ulcer cancer (which means carcinogenesis of chronic gastric ulcer). Microscopically, there are many types of cancer cells by histological classification. For example, the World Health Organization (WHO) classifies gastric cancer into adenocarcinoma (including papillary adenocarcinoma, tubular adenocarcinoma, mucinous adenocarcinoma, and signet ring cell carcinoma (also called mucinous cancer)), adenosquamous carcinoma, squamous cell carcinoma, carcinoid tumors, undifferentiated carcinoma, and unclassified carcinoma by histological classification. China divides gastric cancer into adenocarcinoma (including papillary adenocarcinoma, tubular adenocarcinoma, and mucinous adenocarcinoma), signet ring cell carcinoma (also called mucinous carcinoma), undifferentiated carcinoma, special types of cancer (including adenosquamous carcinoma, squamous cell carcinoma, carcinoid tumors, unclassified carcinoma and mixed type carcinoma), among which, adenocarcinoma accounts for approximately 90%.
Surgical treatment, radiation therapy, targeted therapy, chemotherapy and immunotherapy are often used in treating gastric cancer. In recent years, the number of new cases of gastric cancer in China has ranked first in the world. And nearly 50% of new cases of gastric cancer in the world come from China. Gastric cancer is one of the most common malignant tumors in China, and mortality accounts for the first death of malignant tumors in China. Therefore, it is necessary to develop drugs that can effectively treat gastric cancer.